Button-type batteries are small, thin energy cells that are commonly used in watches and other electronic devices requiring a thin profile. A conventional button-type battery includes two electrodes in the form of an anode and a cathode. These are separated by a porous separator. An electrolyte is present within pores of the separator.
These internal battery components are housed within a metal casing or housing formed by a lower conductive can and an upper conductive lid. A common prior art material for the can and lid is stainless steel. The can is typically in electrical contact with the cathode to form the positive battery terminal, and the lid is in electrical contact with the anode to form the negative battery terminal. The can and lid are crimped or pressed together to form a fluid-tight seal which entirely encloses the anode, cathode, separator, and electrolyte. An electrically insulating sealing gasket is provided within the primary seal between the lid and can to electrically isolate the two housing members.
Typically, the can and lid are separately pre-formed with the anode and cathode materials being inserted after housing formation. One electrode material is elemental lithium, which is typically utilized within the lid as the anode electrode. The typical anode assembly method comprises placing a piece of lithium, already in its finished anode shape, to within the center of a pre-formed lid. The lithium adheres to the lid material, and the lid/lithium composite can then be easily moved in juxtaposition to the cathode can without dislodging the lithium. However, one difficulty with this method concerns handling of the elemental lithium. In short, lithium is sticky and adheres to most everything with which it comes into contact. This makes it extremely difficult for the assembler to appropriately and precisely position the lithium within the lid without it sticking to the insertion tool and other objects.
It would be desirable to develop improved methods of forming button-type lithium electrodes.